1. Field of the Invention
The present invention relates to an apparatus for aligning/supplying electronic component chips, which is adapted to align a plurality of electronic component chips, including electrical parts such as passive and active parts, finished chip components and partially fabricated components, along a prescribed direction for supplying the same. More particularly, it relates to an improvement for smoothing movement of a plurality of electronic component chips within such an apparatus for aligning/supplying electronic component chips.
2. Description of the Background Art
The applicant (assignee) has already proposed a cassette storing electronic components, which is advantageously employed for supplying electronic component chips one by one to a chip mounting station, for example, in Japanese patent application Ser. No. 257926/1986 (corresponding to DE3736692A1, GB2196939A and USP4846345), Japanese patent application Ser. No. 96925/1987 (corresponding to EP0288277A2 and USSN184112, now U.S. Pat. No. 4,889,229), or the like.
This cassette storing electronic component chips basically comprises a plurality of electronic component chips, a case having an internal storage space for storing the electronic component chips and an outlet communicating with the internal storage space for discharging the electronic component chips, and an openable closure for closing the outlet. An electronic component chip manufacturer can directly use such a cassette storing electronic component chips as a packaging mode which is applicable to transportation of electronic component chips, while a user of electronic component chips can directly mount the cassette on a chip mounting apparatus for supplying a plurality of electronic component chips one by one to a chip mounting station.
FIG. 7 is a sectional view illustrating a chip mounting step carried out through such a cassette 1 storing electronic component chips, which is shown in phantom lines. The cassette 1 is directly mounted on a hopper 2 of a chip mounting apparatus. In more concrete terms, the cassette 1 is fixed to the hopper 2 so that its outlet faces an opening 3 of the hopper 2, and a closure of the cassette 1 is opened to supply a plurality of electronic component chips 4, which have been stored in an internal storage space of the cassette 1, into the hopper 2 from the outlet.
The hopper 2 is generally inclined at an angle 5 of inclination of about 45.degree., for example. This hopper 2 comprises a chamber 6 for storing the plurality of electronic component chips 4, and the chamber 6 has a large chamber 7 and a small chamber 8. The electronic component chips 4 supplied into the hopper 2 first flow into the large chamber 7 and then enter the small chamber 8, to finally reach an aligning passage 9. This aligning passage 9 is adapted to guide and move the plurality of electronic component chips 4 in a state aligned with each other along a prescribed direction. In order to achieve this function, sectional dimensions of the aligning passage 9 are selected in relation to the sectional dimensions of each electronic component chip 4.
The small chamber 8 is formed in the vicinity of an inlet 10 of the aligning passage 9, while the large chamber 7 communicates with the small chamber 8.
FIG. 8 is an enlarged perspective view showing the structure provided between the small chamber 8 and a portion close to the inlet 10 of the aligning passage 9. As understood from FIGS. 7 and 8, the small chamber 8 has a bottom wall surface 11 which is flush with a bottom wall surface 12 defining the inlet 10 of the aligning passage 9. In the hopper 2 shown in FIG. 7, the bottom wall surface 11 extends toward the large chamber 7 to form the bottom surface of a groove.
A blowing passage 13 is provided in a portion close to the inlet 10 of the aligning passage 9, in order to introduce compressed air from the exterior in an intermittent manner, for example. The compressed air introduced through the blowing passage 13 blows off and stirs the electronic component chips 4 approaching the inlet 10 of the aligning passage 9. Considering the flow of the electronic component chips 4 within the hopper 2, it is understood that the sectional area of the path for the electronic component chips 4 is abruptly reduced at a portion where the small chamber 8 communicates with the inlet 10 of the aligning passage 9. Thus, an electronic component chip 4 approaching the aligning passage 9 tends to block the inlet 10 and interrupt smooth flow of succeeding chips. In order to prevent this, the compressed air is introduced through the blowing passage 13 in an intermittent manner, for example.
Thus, the plurality of electronic component chips 4 supplied from the cassette 1 pass through the large chamber 7 and the small chamber 8 to approach the aligning passage 9, and are aligned along a prescribed direction to enter the inlet 10. Then the electronic component chips 4 are guided by the aligning passage 9 and discharged from the outlet 14. The electronic component chips 4 discharged from the outlet 14 are aligned in the prescribed direction. Thus, the chip mounting step can be efficiently carried out by retaining the electronic component chips 4 in the aligned state.
FIG. 8 shows no wall surface provided in front of the hopper 2. In practice, such a wall surface (not shown) is positioned along a plane 15, to close the small chamber 8, the aligning passage 9 and the large chamber 7. Therefore, a space defined within the small chamber 8 has a cross-directional size 16. Further, this space has a vertical size 17 on the basis of the bottom wall surface 11, as well as a vertical size 18 on the basis of another part.
FIG. 8 shows three electronic components 4, for example, which are horizontally aligned with each other and nine electronic component chips 4, for example, which are vertically aligned with each other. The total of the cross-directional sizes of the horizontally aligned electronic component chips 4 accidentally coincides with the cross-directional size 16 of the space defined in the small chamber 8. Thus, these electronic component chips 4 unmovably butt against each other between the wall surfaces defining the cross-directional size 16. On the other hand, the total of the perpendicular sizes of the vertically aligned electronic component chips 4 accidentally coincides with the vertical size 17 of the space defined in the small chamber 8. Thus, these electronic component chips 4 unmovably butt against each other between the wall surfaces defining the vertical size 17.
Once such a phenomenon, i.e., the so-called "bridge phenomenon" takes place, it is difficult to separate the electronic component chips 4 which are in such series from each other even if compressed air is introduced through the blowing passage 13.
The aforementioned "bridge phenomenon" is not restricted to the modes shown in FIG. 8, but may occur in various modes in response to relation between the cross-directional and vertical sizes 16, 17 and 18 and the sizes of the electronic component chips 4. In other words, this phenomenon easily takes place when the combination of the longitudinal, cross-directional and perpendicular sizes of the plurality of electronic component chips 4 accidentally corresponds to the cross-directional size 16 or the vertical size 17 or 18 of the space defined in the small chamber 8.
The "bridge phenomenon" is not so frequent but merely occurs in the order of p.p.m. in general. Once the "bridge phenomenon" takes place, however, it is impossible or difficult to supply the electronic component chips 4 to the aligning passage 9. In order to improve workability and reliability of a chip mounting apparatus or the like, therefore, it is desirable to make the probability for the "bridge phenomenon" substantially zero.